Since it is a precursor to substances like epinephrine, norepinephrine, and dopamine, L-tyrosine may be a good supplement choice for those trying to lose weight because, theoretically, it may help speed metabolism. However, it should only be considered for people who also suffer from symptoms such as fatigue and depression.
There are no studies specifically showing that L-tyrosine helps to promote weight loss.
L-tyrosine is best taken without food. Because it can be stimulating, especially when used in large amounts, it should not be taken in the evening. As is the case when supplementing with any individual amino acid, itís possible to upset the balance by taking just one.